Weighing scale indicator



April 1951 F. w. GILCHRIST 2,549,190

wmcnmc some: INDICATOR Filed May 19, 1945 2 Sheets-Sheet 1 I N V EN TOR.Fred W 6776/2/73) ATTORNEYS April 17, 1951 F. w. GILCHRIST WEIGHINGSCALE INDICATOR 2 Sheets-Sheet 2 Filed May 19, 1945 fig 1 Fred @7353,

ATTORNEYS Patented Apr. 17, 1951 WEIGHING SCALE INDICATOR Fred W.Gilchrist, Toledo, Ohio, assignor to Toledo Scale Company, Toledo, Ohio,a corporation of New Jersey Application May 19, 1945, Serial No. 594,737

p 4 Claims.

This invention relates to weighing scale indicators and in particular toa maximum load indicator for use in a sensitive fan scale.

Maximum load indicators when applied to weighing scales introduce smallerrors in the weight indication because of their friction. It isdesirable that the friction be made as low as possible, yet it may bemade so small that the indicator will not remain in position but willmove away from the correct indication if the weighing scale housing isbumped or subjected to vibration. It is possible to satisfactorily addmaximum load indicators to dial scales because a relatively large amountof power is available to overcome their friction. Previous attempts toprovide maximum load indicators for fan scales have met with failurebecause of the small amount of power available at the indicator and theresulting large errors due to variations in friction of the maximum loadindicator.

The object of this invention is to provide a maximum load indicator fora fan scale, which indicator has sufficient friction to prevent erraticmovement yet whose friction is sufiiciently small so as to introducenegligible error into the weight indications.

Another object of the invention is to provide braking means for amaximum load indicator which braking means are releasable by a weighingindicator.

These and other objects and advantages are attained according to theinvention by providing a track fashioned of wire or similar materialthat lies parallel to the path of the weighing scale indicator and aslider or maximum load indicator mounted on the track in such a mannerthat the weighing scale indicator may engage and drive the slider alongthe track. The slider is made as light as possible and is provided withspring means which engage the track to provide a slight amount offriction to hold the slider in position. The spring is so shaped thatwhen it is engaged by the weighing scale indicator to move the slideralong the track it tends to relieve the pressure with which the springengages the track. In this manner suflicient friction is obtained tohold the slider accurately in position and yet the friction issufficiently reduced so that it does not affect the accuracy of weightindication.

The invention as embodied in a weighing scale is illustrated in theaccompanying drawings in which:

Figure I is a front elevation of a weighing scale embodying theinvention.

Figure II is an enlarged fragmentary view showing a portion of thechart, a tip of the weighing indicator and the maximum load indicator asseen from the front of the scale.

Figure III is an elevation of the back side of the indicator housingwith parts broken away so as to show the resetting mechanism used withthe maximum load indicator.

Figure IV is an enlarged sectional view taken substantially along theline IVIV of Figure III showing the mounting of the resetting mechanism.

Figure V is a fragmentary detail showing the tip of the weighing scaleindicator engaged with the maximum load indicator as seen from the backof the scale.

Figure VI is a fragmentary plan view showing the engagement of theweighing scale indicator and the maximum load indicator as seen from theline VIVI of Figure V.

Figure VII is a plan view of the maximum load indicator.

Figure VIII is a fragmentary vertical section taken along the lineVIII-VIII of Figure V.

Figure IX is a fragmentary view of the tip of the weighing scaleindicator as seen from the line IX--IX of Figure VI.

These specific drawings and the accompanying description merelyillustrate a preferred form of the invention and are not intended. toimpose limitations on the claims.

The improved form of maximum load indicator is incorporated in aweighing scale of the even arm type as shown in Figure I. This scalecomprises a base housing I and a pendulum and indicator housing 2erected thereon. A lever system 3 mounted in the base I supports a loadreceiving platform 4 and a counterweight receiving platform 5. In thisarrangement a major part of the weight of the load on the receivingplatform 4 may be counterbalanced by known weights applied to thecounterweight, platform 5 while the excess not so counterbalanced iscounterbalanced by a pendulum 6 connected to the lever system 3 througha flexible tape I. The pendulum 6 is supported on a knife edge 8, isprovided with a sector shaped cam 9 to which the flexible tape I isattached, and is further provided with an indicator portion I0 whoseindex tip I I cooperates with indicia I2 on a chart I 3 to indicate themagnitude of the load being counterbalanced by the pendulum 6.

To permit the weighing scale to be used to register the maximum forcesustained by a test specimen prior to failure the weighing scale shownin Figure I is provided with a maximum load indicator assembly l4. Themaximum load indicator l4 adapted to slide along a wire track l5 whichat each end of the chart is securely held in brackets 16. The wire track15 strictly conforms to the curve of the reading line of the chart l3and lies parallel thereto and slightly to the rear of the plane of thechart. The maximum load indicator [4 lies entirely behind the chart l3and is equipped with a flat front face I! on which an index line H! isinscribed, which is visible through an arcuate slot 19 cut in the chart[3 along its reading line.

The front face I! of the maximum load indicator i4 is mounted on aninturned end 20 of a U-shaped slider 2! (shown in detail in Figure VII).Holes through the legs of the U-shaped slider 2! allow it to be threadedonto the wire track E5 in such position that the front face I! liesparallel to and immediately behind the slot IS in the chart IS. A springbrake 22 formed by bending a piece of flat stock into an L-shape isriveted to the bottom of the U-shaped slider 2| such that its long arm23 lies parallel to the bottom of the U and its short leg 24 liesgenerally parallel to the short leg of the slider. A hole 25 cut in theshort leg 24 of the L-shaped spring brake 22 accommodates the wire track[5. The spring brake 22 is tensioned so that its long arm 23 restslightly against the wire track 15 so as to prevent the indicatorassembly l4 from freely sliding along the track 15. The indicatorassembly M is driven along the track l5 by pushing against the short arm24 of the L-shaped spring. The pushing force is in such a direction thatit tends to relieve the spring pressure against the track :5 to permitthe indicator assembly to slide forward freely as long as there iscontact between the short arm 24 of the spring and the weighing scaleindicator H}.

The tip of the weighing scale indicator behind its index portion H isprovided with a U- shaped hook 26. The hook 26 is fashioned by cutting aU-shaped piece from flat stock, then bendup-turned leg 27 is riveted tothe rear surface v of the indicator tip H such that the remaining leg 28extends through the slot I9 in position to pass behind the lower end ofthe front face I! of the maximum load indicator 14. The end of theup-turned leg 22' is adapted to strike the short leg 24 of the springbrake 22 so as to drive the maximum load indicator along with theweighing scale indicator [0. This driving engagement which permitsregistration of the index line 18 and the index H is most clearly shownin Figure VI.

The maximum load indicator I4 is thus adapted to be positioned anywherealong the track l by movement of the indicator H3. The operation isperformed by the indicator ID advancing so that the arm 28 of the hook25 passes behind the front face I! of the maximum load indicator l4thereby ensuring that the up-turned leg 21 of the hook positivelyengages the end 24 of the L-shaped brake spring 22 to release the brakeand allow the maximum load indicator M to freely slide along the track15,

After the reading of the maximum load indicator M has been noted theindicator [4 must be returned to a point near zero on the chart inpreparation for the next cycle of operation. A reset sweep 29 mounted inthe indicator housing 2 behind the lower portion of the chart l3terminates in a fiat spring 30 adapted to slide along the wire track [5and push the indicator [4 towards zero. The sweep 29 is carried on ashaft 3| which is journaled in a short sleeve 32 soldered or otherwisesecured to the top of a pivot retainer 33 of the weighing scalemechanism. The exterior end of the shaft 31 is provided with a knob 34to permit easy manipulation. A Wire spring 35 coiled around a portion ofthe sleeve 32 engages the pivot retainer 33 and the sweep arm 29 and istensioned to urge the sweep arm 29 away from the zero end of the chartl3. The spring 35 also serves to hold a coupling 36 by which the sweeparm 29 is held to the shaft 31 closely in contact with the journalingsleeve 32. The spring 35 prevents the return sweep from beinginadvertently left in such a position that it would interfere with thenormal operation of the scale.

To prevent any damage to the scale by improper use of the reset sweep 29its travel toward the zero end of the scale is limited by a stop 31. Thestop 3'! is a piece of strip stock secured to the frame of the indicatorhousing 2 and projects lengthwise toward the path of the reset sweep 29.It is given a twist about its longitudinal axis so that its free endlies transverse the plane of movement of the reset sweep 29 and istherefore adapted to positively engage the sweep to prevent anyovertravel thereof.

The objects of the invention are attained in this simple maximum loadindicator because those parts which must be moved by the indicator arelight in weight and the friction between the maximum load indicator andthe track on which it runs is reduced during the time the maximum loadindicator is being driven by the weighing scale indicator.

Having described the invention, I claim:

1. In a device of the class described, in combination, an automaticweighing scale having a generally fan-shaped chart and an indicatormovable thereover, a track mounted on the chart and extending along thepath of the indicator, an index slidably mounted on said track, aresilient member on said index that frictionally engages the track andthat has a portion extending into the path of the indicator, saidindicator being adapted to engage said portion to reduce the frictionbetween said member and said track and to move said index along saidtrack.

2. In a device of the class described, in combination, an automaticweighing scale having a chart and an indicator, said chart havingindicia disposed along the edge of an arcuate slot extending along thepath of the indicator, an offset tip on said indicator adapted to lie insaid slot, 2. track secured to the back of the chart and extending alongthe slot, an index mounted on said track adjacent to and visible throughsaid slot, a resilient member in said index for frictionally engagingsaid track, said resilient member projecting into the path of theindicator and being adapted to reduce its frictional engagement with thetrack when engaged by the indicator whereby said indicator may drivesaid index along said track.

3. In a maximum load indicator for an automatic weighing scale employinga movable indicator, a track positioned closely parallel to the path ofthe indicator, said track being supported only at its ends, and a slidermounted on said track, said slider comprising a formed U-shaped memberhaving openings in its side which engage said track, and a springsecured to said member and adapted to frictionally engage said track.

4. In a maximum load indicator for an automatic weighing scale employinga movable indicator, a track positioned closely parallel to the path ofthe indicator, said track being supported only at its ends, and a slidermounted on said track, said slider comprising a formed U-shaped memberhaving openings in its sides which engage said track, and a springsecured to said member in position to frictionally engage said trackand. to be deflected from its track engaging position when contacted bysaid movable indicator.

FRED W. GILCHRIST.

file of this patent:

Number Number UNITED STATES PATENTS Name Date Swoboda May 16, 1899Harris Jan. 2, 1900 Kraft et a1 July 4, 1922 Paine Aug. 14, 1923 Powell1- Mar. 4, 1924 Hapgood Nov. 16, 1926 Hapgood Mar. 27, 1928 Pollack Feb.'16, 1932 Wende Nov. 29, 1932 Fryer May 16, 1933 Cox May 11, 1937 StokesJuly 6, 1943 Kahn Dec. 26, 1944 FOREIGN PATENTS Country Date GermanyMar. 31, 1931 Great Britain Feb. 1, 1937

